Audio players include digital music players capable of handling digital audio files in one or more file formats. Several formats for digital audio files exist, each offering its own combination of sound quality, compression rate, streaming capability, and other features. Some of the existing file formats are: AAC, ATRAC, MP3, AIFF, WMA, OGG, and WAV, but this list is not an exhaustive one. Portable audio players capable of playing digital audio files, and of storing them in large numbers, have become very popular. Such players are often referred to as MP3 players because of the popularity of that particular file format.
Transmitters have been developed in order to enable playback of stored digital audio files over speakers external to the portable audio player. As an example, such transmitters make it possible to play a song stored in the portable audio player over a car stereo. Wireless FM transmitters enable such playback on a locally-unused frequency of the FM spectrum without the need for cables or other connections between the player and the stereo. Existing transmitters, however, lack versatility in terms of the power sources with which they are compatible. This lack of versatility limits their usefulness. Accordingly, there exists a need for a transmitter system capable of interfacing with an audio player in a way that overcomes the limitations of the existing devices.
For simplicity and clarity of illustration, the drawing figures illustrate the general manner of construction, and descriptions and details of well-known features and techniques may be omitted to avoid unnecessarily obscuring the invention. Additionally, elements in the drawing figures are not necessarily drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help improve understanding of embodiments of the present invention. The same reference numerals in different figures denote the same elements.
The terms “first,” “second,” “third,” “fourth,” and the like in the description and in the claims, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms “comprise,” “include,” “have,” and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements is not necessarily limited to those elements, but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.
The terms “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and the like in the description and in the claims, if any, are used for descriptive purposes and not necessarily for describing permanent relative positions. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the invention described herein are, for example, capable of operation in other orientations than those illustrated or otherwise described herein. The term “coupled,” as used herein, is defined as directly or indirectly connected in an electrical, mechanical, or other manner.